1. Field of the Invention
The present invention relates to a radiographic image capturing apparatus including a radiation source device which houses a radiation source therein and a cassette which houses a radiation detector therein, and a radiographic image capturing method for detecting a radiation output from the radiation source with the radiation detector and converting the detected radiation into a radiographic image.
2. Description of the Related Art
In the medical field, there have widely been used radiographic image capturing apparatus which apply a radiation to a subject and guide the radiation that has passed through the subject to a radiation conversion panel (radiation detector), which captures a radiographic image from the radiation. Known forms of the radiation conversion panel include a conventional radiation film for recording a radiographic image by way of exposure, and a stimulable phosphor panel for storing a radiation energy representing a radiographic image in a phosphor and reproducing the radiographic image as stimulated light by applying stimulating light to the phosphor. The radiation film with the recorded radiographic image is supplied to a developing device to develop the radiographic image, or the stimulable phosphor panel is supplied to a reading device to read the radiographic image as a visible image.
In the operating room or the like, it is necessary to read a recorded radiographic image immediately from a radiation conversion panel after the radiographic image is captured for the purpose of quickly and appropriately treating the patient. As a radiation detector which meets such a requirement, there have been developed a radiation detector of the direct conversion type having a solid-state detector for converting a radiation directly into an electric signal and a radiation detector of the indirect conversion type having a scintillator for temporarily converting a radiation into visible light and a solid-state detector for converting the visible light into an electric signal.
As disclosed in Japanese Laid-Open Patent Publication No. 10-225450 and Japanese Laid-Open Patent Publication No. 2007-222604, the radiographic image capturing apparatus are developed on the assumption that they will be used to capture radiographic images of patients in hospitals.
There are potential demands for capturing radiographic images outside hospitals. To meet such demands, radiographic image capturing apparatus mounted on motor vehicles dedicated for medical examination have been proposed in the art. However, the proposed radiographic image capturing apparatus on the medical examination motor vehicles are relatively large in size. Needs have arisen for capturing radiographic images of persons who suffer from natural disasters at the disaster sites or persons who are receiving home-care services at their homes. However, the existing medical checkup motor vehicles cannot be used in the former application as they find it difficult to get to disaster sites. Though the existing medical checkup motor vehicles may be driven to the homes of persons who are receiving home-care services, the image capturing process is highly burdensome to the people to be imaged because they have to be taken from their homes into the medical examination motor vehicle in order to capture radiographic images thereof. Therefore, there have been demands for small-size portable radiographic image capturing apparatus for use at natural disaster sites or homes receiving home-care services.
There has been developed a portable radiographic image capturing apparatus which can be folded into a compact form in its entirety as disclosed in Japanese Laid-Open Patent Publication No. 11-104117. In addition, field-emission-type radiation sources based on the carbon nanotube (CNT) technology have also been proposed as disclosed in Japanese Laid-Open Patent Publication No. 2007-103016 and AIST: Press Release “Development of Portable X-ray Sources Using Carbon Nanostructures” [online], Mar. 19, 2009, National Institute of Advanced Industrial Science and Technology, [retrieved Jul. 8, 2009, Internet <URL: http://www.aist.go.jp/aist_j/press_release/pr2009/pr20090319/pr20090319.html>. It has been expected to have small-size, lightweight radiographic image capturing apparatus including radiation sources, available in the art.
When a radiographic image capturing apparatus including a radiation source is reduced in overall size and weight, it is easy to carry around. Specifically, the doctor or radiological technician in charge carries the radiographic image capturing apparatus in its compactly folded form to a disaster site or a home receiving home-care services. At the disaster site or the home, the doctor or radiological technician assembles the radiographic image capturing apparatus into an operational form so that it is ready to capture radiographic images. After having captured radiographic images, the doctor or radiological technician folds the radiographic image capturing apparatus into the compact form again. The portable radiographic image capturing apparatus needs to be assembled and readied for capturing radiographic images each time it is carried to a different site. Consequently, it is desirable to make the portable radiographic image capturing ready to capture radiographic images simply in a short period of time.